White phosphorus exists as P 4 molecules with phosphorus atoms at the corners of a tetrahedron (a) Elemental phosphorus reacts with Cl 2 to form PCl 3 Write a balanced chemical equation for this reaction (b) The standard enthalpy of formation ( f H) of P 4 (g) is 58 9 kJ mol for PCl 3 (g) it is 287...

a Balanced chemical equation P4s 6C128 4 PC13E b AHrxn AH products AH r ...

White phosphorus exists as P 4 molecules with phosphorus atoms at the corners of a tetrahedron. (a)

Question:

White phosphorus exists as P₄ molecules with phosphorus atoms at the corners of a tetrahedron. White phosphorus, P4

(a) Elemental phosphorus reacts with Cl₂ to form PCl₃. Write a balanced chemical equation for this reaction.
(b) The standard enthalpy of formation (Δ_f H°) of P₄(g) is +58.9 kJ/mol; for PCl₃(g) it is −287.0 kJ/mol. Use these numbers to calculate the enthalpy change for the reaction of P₄(g) and Cl₂(g) to give PCl₃(g).
(c) Based on the equation in (a), determine what bonds are broken and what bonds are formed. Then, use this information along with the value of Δ_rH° calculated in (b) and the bond dissociation enthalpies for the P—P and Cl—Cl bonds from Table 8.8 to estimate the bond dissociation enthalpy for the P—Cl bonds. How does your estimate compare with the value in Table 8.8?

Data given in Table 8.8

TABLE 8.8 Some Average Bond Dissociation Enthalpies (kJ/mol)* Single Bonds F Si 328 H C N 0 F Si P S CI Br B